A Formal Hierarchy of RNN Architectures William Merrill author Gail Weiss author Yoav Goldberg author Roy Schwartz author Noah A Smith author Eran Yahav author 2020-07 text Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics Dan Jurafsky editor Joyce Chai editor Natalie Schluter editor Joel Tetreault editor Association for Computational Linguistics Online conference publication merrill-etal-2020-formal 10.18653/v1/2020.acl-main.43 https://aclanthology.org/2020.acl-main.43/ 2020-07 443 459